Rapid fabrication of micro- and nanoscale patterns by replica molding from diatom biosilica

Dusan Losic, James G. Mitchell, Ratnesh Lal, Nicolas H. Voelcker

Research output: Contribution to journalArticleResearchpeer-review

133 Citations (Scopus)

Abstract

Diatoms are single-celled micro-algae that possess an exoskeleton (called frustule) comprised of diverse and highly ordered 3D porous silica structures and that hold considerable promise for biological or biomimetic fabrication of nanostructured materials and devices. We have used, for the first time, a soft lithographic approach of replica molding to replicate porous diatom structures into polymers. Two centric diatom species, Coscinodiscus sp., Thalassiosira eccentrica cultured in our laboratory were used as masters for replication. In the first step, replica molding onto soft and elastic polymer using poly(dimethylsiloxane) PDMS produced a negative replica of the diatom frustule. These PDMS replicas were then used as a mold to fabricate the positive polymer replicas of diatoms using a mercaptol ester type UV curable polymer (NOA 60). Fabricated polymer replicas were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). In all cases, diatom micro- and nanoscale porous structures were successfully transferred with high precision into polymer replicas. Such an accomplishment effectively demonstrates the potential for using diatoms as blueprints for rapid and simple fabrication of polymer nanostructures. The prepared replicas were used as diffraction gratings and as nanowells to hold polymeric nanoparticles effectively demonstrating the functional properties of these biomimetic structures.

Original languageEnglish
Pages (from-to)2439-2446
Number of pages8
JournalAdvanced Functional Materials
Volume17
Issue number14
DOIs
Publication statusPublished - 24 Sep 2007
Externally publishedYes

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